The invention disclosed herein relates generally to stop pin apparatus and particularly to stop pins that are inserted between the walls or plates of a housing to limit the movement of a gear or other member which is located within the housing.
Although the invention will be described in relation to an environment of limiting the rotation of a sector gear of an actuator it will be understood that there is a need for the stop pin apparatus in other environments.
In the past various types of stop pin apparatus have been used including a bolt and nut arrangement. However, changes in the stop pin location require access to both sides of the actuator and removal and reattachment of the nut. For these reasons this is generally not a desirable type of stop pin.
A simple clevis pin has been used. This device includes a shaft having a headed end and a radial bore at the opposite end for receiving a cotter key. This method requires insertion of a cotter key and would require removal and reinsertion of the cotter key if it is necessary to change the location of the stop pin. The manipulation of the cotter key and the need for tools is undesirable in many stop pin applications.
A clevis pin or coupling pin type device that includes a latching means has been used. These devices typically include an axial bore extending substantially through the pin and two opposed radial bores at the insertion end. Two balls are disposed in the radial bores and a shaft having an annular groove is disposed in the axial bore. With the shaft in a first position the balls are received in the annular groove and do not protrude beyond the surface of the pin. This allows the pin to be inserted through a hole in a plate. With the shaft in a second position the balls are forced outwardly and protrude beyond the surface of the pin to engage a surface of the plate. Various means are used to move the shaft between the first position and the second position. While this type of clevis pin can be used for a stop pin application it is a more complex device than is needed.
Thus a need exists for a simple stop pin apparatus that can be easily inserted and removed and does not require the use of tools.